Extremely low frequency magnetic fields in the work environment

Abstract

The presence in the environment of extremely low frequency (ELF) magnetic fields results from electrical power distribution and the increased use of electrical devices within households and workspaces. ELF magnetic fields can induce currents inside the human body which are weak and lower than the body's natural currents. However, studies abroad have shown that industrial activities could lead workers to be overexposed to ELF magnetic fields. The aim of this study was to determine, for the first time in Malta, whether two specific work environments, namely an office and a welding workshop, pose a risk to workers due to exposure to ELF magnetic fields higher than the thresholds established in EU adopted Directive 2013/35/EU which mandates maximum exposure levels of workers to non-ionising electromagnetic fields. The main objective of the research was to measure the magnetic flux density present within the chosen environments and to compare the values with the thresholds set by the EU Directive. For the office environment, the NARDA model EFA200 magnetic field survey meter was used to measure and show graphically the fields within the accessible areas. Since the meter allows the Fast Fourier Transform (FFT) mode of operation, frequency spectra were also taken at the hotspots. For the welding workshop, apart from measurements taken by the same survey meter in close proximity to the welder, a jig was constructed to simulate and measure the different welding cable scenarios. The welding practices investigated are the most commonly used in the Maltese Islands. The magnetic flux densities for each at the hotspots were measured and the c01Tesponding FFTs were recorded.